Do we owe our attraction to alcohol to our monkey cousins?

For the past ten years, researchers have imagined that our human inclination for alcohol could be inherited from our cousins ​​the monkeys. This is the so-called hypothesis of “drunken monkey”. Today, a team confirms that some particularly appreciate fermented fruits. Not to get drunk, but because these are higher in calories.

As a child, Robert Dudley lived alongside an alcoholic father. This is what motivated him to study the mechanisms of this disease. For 25 years now, the evolutionary biologist has been questioning the subject. In 2014, he hypothesized the “drunken monkey”. Who wants that our cousins ​​and our ancestors were particularly attracted by the alcoholic fruits by the fermentation natural. From very ripe fruit and nutritionally rich. A hypothesis that now seems to want to confirm a study carried out in Panama by University of California researchers (United States).

Primatologists have studied fruit eaten by black-handed spider monkeys, also known as Geoffroy’s spider monkeys (Ateles geoffroyi). They observed that the favorite fruits of these monkeys have a concentration of alcoholresulting from the natural fermentation of sugar under the effect of yeasts, which varies between 1% and 2% in volume – certain concentrations can go up to 7%. These fruits are those of the mombin plum tree (Spondias mombin). They are a major part of the diet of black-handed spider monkeys. And these same fruits have been used for millennia by the indigenous human populations of Central and South America to make chicha, a alcoholic drink fermented.

But even if they smell the fruit before eating it, the researchers do not imagine that the monkeys are trying to get drunk in this way. They also observed that the urine of these monkeys contains metabolites side effects of alcohol — ethyl glucuronide and ethyl sulfate. A proof of the use of this alcohol by monkeys to produceenergy. Because fermented fruits would be richer in calories.

A new way to treat alcoholism?

So the monkeys probably don’t feel the intoxicating effects alcohol that humans enjoy so much. For they fill themselves with fruit before the drunkenness can be felt. Especially since the alcohol content of these fruits is about half that of our least alcoholic drinks. ” But it does provide black-handed spider monkeys with physiological benefits. “says Robert Dudley in a statement from the University of California. “Maybe there is also an antimicrobial benefit in the foods they eat. »It is possible that the activity of yeast and germs predigest the fruit.

The researchers believe that the choice to place these alcoholic fruits at the center of their diet may have been made by our human ancestors for the same reasons. Because they were higher in calories. “The psychoactive and hedonic effects of ethanol may also lead to increased consumption rates and caloric gain”says Christina Campbell, the primatologist who led the study.

A phenomenon that is even greater today when alcohol is readily available in the form liquid. Rid of fruit pulp that fills the belly. Thus, the researchers assume, as the diabetes and theobesityalcoholism may need to be considered a diet-related disease.